CN102015620A - Method for preparing combretastatin - Google Patents

Abstract

The present invention relates to a method for preparing combretastatin (A) in base form or acid addition salt form, the method comprising coupling a salt of a (Z)-amino compound of formula (II) with a doubly protected L-serine derivative of formula (III) (wherein PG represents a group protecting the amino functional group) in the presence of a base and T3P, thereby obtaining a compound of formula (Z)-(Ib): formula (IV), then deprotecting and opening the ring of (Z)-(Ib) in the presence of an acid, thereby obtaining combretastatin (A) in salt form, and optionally, adding a base, thereby obtaining combretastatin (A) in base form, wherein the salt of the (Z)-amino compound is obtained by enriching a salt of an amino compound of formula (V) in the form of a (Z) isomer.

Description

Method for preparing combretastatin

technical field

The present application relates to a process for the preparation of combretastatin (combretastatin) (A) in base form or acid addition salt form

Background technique

US 6 759 555 describes a process for the preparation of combretastatin having the formula

Wherein, X represents -NH ₂ or one of the following two groups:

PG denotes a group protecting the amino function.

Bioorg. Med. Chem. 2000, 8, 2417-2425 and US 2003/0220404 also describe methods for the preparation of combretastatin.

J. Pept. Res. 1999, 54(1), 54-65 compares acid activators for forming peptide bonds and concludes that TDBTU is the best.

Bioorg. Med. Chem. 2006, 14, 3231-3244 describes the preparation of combretastatin of formula (A) using DCC as acid activator for the coupling of HOBt-H ₂ O (step e, compound 10).

Chem. Commun. 1999, 1847-1848 describes T3P in the preparation of amide bonds; however, T3P is described as giving rise to more epimerization and the resulting yields are worse than HAPyU (see Table 3).

These documents neither describe nor imply a method which is the subject matter of claim 1 . Similarly, neither the enrichment of amino compound salts using benzyl alcohol and acetonitrile nor the coupling using T3P is described.

technical problem

Combretastatin or stilbene derivatives exhibit strong cytotoxic activity and as a result can be used as anticancer agents. However, it was the (Z) isomer that exhibited the strongest cytotoxic activity. These compounds are specifically described in US 5 731 353, US 5 561 122 or US 6 759 555. The present application improves the method for preparing combretastatin (A).

Contents of the invention

The present invention relates to a method for the preparation of combretastatin (A) in base form or acid addition salt form:

The method comprises: in the presence of a base and T3P having the following formula (III):

或使(Z)-氨基化合物的盐

与具有式

的双保护的L-丝氨酸衍生物偶联，从而得到具有式(Z)-(Ib)的化合物：

Make (Z)-amino compounds

Or make the salt of (Z)-amino compound

with type

The double-protected L-serine derivatives of the coupling, thus obtain the compound with formula (Z)-(Ib):

Wherein B ^- represents a counteranion (counteranion), PG represents a group protecting the amino functional group; then in the presence of an acid, deprotection and opening of the ring of (Z)-(Ib) are carried out to obtain the salt (-NH ₃ ⁺ ) form Combretastatin (A); and optionally, adding a base, thereby obtaining Combretastatin (A) in the form of base (-NH ₂ ),

The salt of the (Z)-amino compound is obtained by enriching the salt of the amino compound in the form of the (Z) isomer having the following formula:

Wherein B ^- represents a counter anion, and said enrichment includes:

Benzyl alcohol is added to a suspension of the mixture of the salt of the (Z)-amino compound and the salt of the (E)-amino compound in acetonitrile, then

• Mechanical separation of the salt of the amino compound enriched in the (Z) isomer.

The present invention also relates to a method of enriching the salt of an amino compound having the formula in the form of the (Z) isomer

Wherein B ^- represents a counter anion, and the method comprises:

adding benzyl alcohol to a suspension of the mixture of the (Z)-amino compound salt and the (E)-amino compound salt in acetonitrile, and

• Mechanical separation of the salt of the amino compound enriched in the (Z) isomer.

The present invention also relates to the use of T3P having the formula (III),

The T3P of formula (III) is used to couple (Z)-amino compounds or salts of (Z)-amino compounds with double-protected L-serine derivatives in the presence of a base.

The ratio of acetonitrile/salts of (Z)- and (E)-amino compounds is 5 to 17, preferably 10 to 12 by weight. The temperature at which the enrichment is carried out is preferably from 20 to 70°C. The ratio of benzyl alcohol/salts of (Z)- and (E)-amino compounds is 1 to 4, preferably 2 to 3 by weight.

Detailed ways

Scheme 1 below describes the reaction steps (i) to (iv) of the process for the preparation of combretastatin (A):

plan 1

Step (i) : carry out the Witting reaction (Witting reaction) between nitromethoxybenzaldehyde and trimethoxybenzylphosphonium bromide or trimethoxybenzylphosphonium chloride in the presence of a base to obtain nitro A salt of a compound which is the two (Z) and (E) isomers of 2-methoxy-5-[2-(3,4,5-trimethoxyphenyl)vinyl]nitrobenzene ( (Z)-nitro and (E)-nitro) in the form of a mixture;

Step (ii) : Reduction of the mixture to obtain a mixture of (Z)-amino compound and (E)-amino compound, wherein (Z)-amino compound and (E)-amino compound are converted into a salt (B ^- represents a counter anion, For example Cl ^- or SO ₄ ^2- ), followed by the step of isolating (Z)-amino compounds;

Step (iii) : coupling of the salt of (Z)-amino compound with L-serine derivative (compound of formula (II)) doubly protected on -OH and amino functional groups to obtain compound (Z)-(Ib );

PG denotes a group protecting the amino function: it may be, for example, tert-butoxycarbonyl (BOC), benzyloxycarbonyl (CBZ) or 9-fluorenylmethoxycarbonyl (FMOC);

Steps (iv) and (v) : Deprotection and ring opening are performed to obtain combretastatin (A) in salt or non-salt form.

Step (i) is described in US 5 731 353 and in Bioorg. Med. Chem. 2000, 8, 2417-2425 (Scheme 1). The reaction is carried out in an organic solvent such as an aromatic solvent (eg toluene) in the presence of a base, preferably a strong base such as MeONa or NaH. The ratio (Z)/(E) is of the order of 75/25.

The reduction step (ii) described in US 6 759 555 is carried out in the presence of an excess of iron (more than 2 equivalents relative to (Ia)). Reduction in the presence of zinc was also possible as described in US 5 525 632 (example 2, step 2), but the reduction was incomplete (yield = 49.3%) and moreover resulted in the formation of large amounts of "azo" by-products. The (Z)-amino compound is subsequently obtained in sufficient purity by one or more complicated separations. Isolation followed by reduction is carried out by successive crystallization. A first crystallization can remove the (E)-amino compound and a second crystallization can isolate the (Z)-amino compound (see, US 6 759 555, Example 1).

Coupling step (iii) is advantageously carried out in the presence of an acid activator such as EDCI (1-(3-dimethylaminopropyl)-3-ethylcarbodiimide chloride, DCC (Dicyclohexylcarbodiimide), TOTU(O-[ethoxycarbonyl]cyanomethyleneamino)-N,N,N',N'-tetramethyluronium tetrafluoroborate (O -[ethoxycarbonyl]cyanomethyleneamino)-N,N,N',N'-tetramethyluroniumtetrafluoroborate)), HBTU(O-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexa fluorophosphate), PivCl (pivaloyl chloride) or N,N-carbonyldiimidazole (carbonyldiimidazole). The term "acid activator" ("coupling agent") is used to denote a compound that functions to activate the acid function -COOH to facilitate the formation of peptide bonds. For a more detailed description of acid activators, refer to the review ChemFiles Vol.7, No.2, page 3 (published by Aldrich Chemical Company) or see Tetrahedron report No.672, 2004, 60, 2447-2467, "Recent development of peptide coupling reagents in organic synthesis". The review Tetrahedron 2005, 61, 10827-10852 discloses that many acid activators are available.

Step (iv) is carried out in the presence of an acid in order to facilitate ring opening and obtain combretastatin (A) in the form of a salt (-NH ₃ ⁺ ). It involves deprotection/ring opening. In the presence of BOC, hydrochloric acid is advantageously used, for example in the form of a solution in methanol, to give the hydrochloride salt. The base form of combretastatin (A) is obtained by neutralizing the salt with a base such as sodium hydroxide (see eg Example 1 - step (iii)).

Method of the invention

The method of the present invention repeats the same steps of scheme 1, but improves steps (ii) and (iii). Indeed, in the present invention, during step (ii), the (Z) isomer of the salt of the amino compound is obtained by a process comprising:

adding benzyl alcohol to a suspension of the mixture of the (Z)-amino compound salt and the (E)-amino compound salt in acetonitrile, and

• Mechanical separation of the salt of the amino compound enriched in the (Z) isomer.

Thus, the (Z) isomer is obtained by "enrichment", a term which refers to an increased ratio of the (Z) isomer relative to the (E) isomer at the end of the two steps of the above process; And a method for separating the (Z) isomer from a mixture of the (Z) isomer and the (E) isomer. The advantage of enrichment over (re)crystallization is that it is straightforward and simple to perform. This amino compound can be obtained enriched in the (Z) isomer with low residual (E) isomer content (which can reach <1 mol %; see Example 1, where for the (Z) isomer, the product The purity of is 99.93% and for the (E) isomer it is 0.07%). Mechanical separation can be, for example, filtration or centrifugation. At the end of the mechanical separation, the salt of the (Z) isomer can optionally be washed and dried.

The suspension preferably has an acetonitrile/(Z)- and (E)-amino compound salt ratio of 5 to 17, preferably 10 to 12 by weight (i.e. the weight of acetonitrile in the suspension is (Z)- and (E)-5 to 17 times the weight of the amino compound).

The amount of benzyl alcohol added is preferably such that the ratio of benzyl alcohol/salts of (Z)- and (E)-amino compounds is 1 to 4 by weight, preferably 2 to 3 (i.e., the weight of benzyl alcohol added 1 to 4 times the weight of (Z)- and (E)-amino compounds). This ratio makes it possible to maintain a high (Z)/(E) ratio for the final product. Benzyl alcohol acts to preferentially dissolve the salt of the (E)-amino compound.

The temperature at which the enrichment is carried out is preferably from 20 to 70°C, advantageously from 30 to 70°C, preferably from 35 to 65°C. Above 70°C, the amino compound begins to decompose slowly.

其可以用有机溶剂例如氯化溶剂如二氯甲烷(DCM)提取。强酸的醇溶液加入到有机相中，然后用乙腈置换醇，得到(Z)-和(E)-氨基化合物的盐在乙腈中的悬浮液。强酸可以是HCl或H₂SO₄(B^-＝Cl或SO₄ ^-)。可以在真空下或多或少完全除去醇之后通过添加乙腈来进行该溶剂置换。可以伴随着在真空下除去醇时进行乙腈的加入。醇优选为轻醇(light alcohol)，例如甲醇或乙醇。A preferred method for preparing the suspension is described below. The (Z)- and (E)-nitro compounds are reduced using sodium dithionite (Na ₂ S ₂ O ₄ ) in a solvent, which may be a mixture of water and alcohol, such as a water/methanol mixture. After reduction, a strong acid (eg, HCl or _H2SO4 ) is introduced into the reaction medium, which reacts with the reaction intermediates and _also with dithionite and disulphite residues. A mixture of salts of (Z)- and (E)-amino compounds (eg hydrochloride or sulfate) is then obtained. Then, a strong base is added to obtain the free base

It can be extracted with organic solvents such as chlorinated solvents such as dichloromethane (DCM). The alcoholic solution of the strong acid is added to the organic phase and the alcohol is then displaced by acetonitrile to obtain a suspension of the salts of the (Z)- and (E)-amino compounds in acetonitrile. The strong acid can be HCl or H ₂ SO ₄ (B ⁻ =Cl or SO ₄ ⁻ ). This solvent exchange can be carried out by adding acetonitrile after more or less complete removal of the alcohol under vacuum. The addition of acetonitrile can be performed concomitantly with removal of the alcohol under vacuum. The alcohol is preferably a light alcohol such as methanol or ethanol.

For step (iii), in an organic solvent in the presence of a base, use propanephosphonic acid anhydride (T3P) as acid activator, carry out the salt of (Z)-amino compound and the double protection with formula (II) Coupling between L-serine derivatives. The role of the base is to trap the acid species, moving the salt towards the free base. The amount of base added is 2 to 3 equivalents relative to the salt of the (Z)-amino compound (see Example 1 where 2.7 equivalents were used). It is also possible to directly couple the (Z)-amino compound with the compound of formula (II) in the presence of T3P and a base; in this case, the amount of base added is relatively small, 1 to 2 equivalents (when starting from the salt when about less than 1 equivalent).

The base can be a tertiary amine such as triethylamine (TEA), diisopropylethylamine (DIEA), N-methylmorpholine (NMM) or methylpiperidine. The organic solvent can be dichloromethane (DCM), toluene, methyl isobutyl ketone (MIBK), ethyl acetate, acetonitrile, tetrahydrofuran (THF), Me-tetrahydrofuran (Me-THF), or cyclopentyl methyl ether.

T3P has the following formula:

The advantage of using T3P rather than another acid activator is that by-products of T3P can be easily removed (both by-products are water soluble) and that it is an inexpensive activator. Furthermore, the reaction can be carried out in the presence of (Z)-amino compound (salt or base form) and compound (II), brought together according to the "one-pot method": in the presence of T3P and base, (Z)-amino Compound (salt or base form) and compound (II) are thus reacted together in the same vessel. This is not true for all coupling reagents as some coupling reagents such as PivCl (pivaloyl chloride) require pre-activation of the acid of compound (II) for the same reaction before the salt of the (Z)-amino compound can be added functional group.

Finally, we note that T3P does not lead to epimerization of the asymmetric center, whereby combretastatin (A) can be obtained in good purity and good yield. It has also been noted that T3P gives good yields of coupled products (see Table III).

The coupling reaction is usually carried out at a temperature of 5°C to 70°C, for example under reflux of DCM. The ratio of T3P to the (Z)-amino compound is 1 to 2 equivalents, preferably 1.5 to 1.8 equivalents.

Example

Embodiment 1 (according to the present invention)

Step (i):

At a temperature of 5-10° C., sodium methoxide solution (5.66 kg, 29.34 mol) was flowed into a mixture containing toluene (91.1 liters), trimethoxybenzylphosphonium bromide (15.35 kg, 29.33 mol) and 4- Methoxy-3-nitrobenzaldehyde (5.06 kg, 27.93 mol). At the end of the reaction, 0.32 liters (5.59 mol) of acetic acid flowed in. After the medium was kept at 20°C, it was filtered. The filter cake was washed with toluene (11.1 L). The filtrate was washed several times with water (20.2 L), then concentrated under vacuum. Isopropanol (87.6 L) was then introduced, the medium was concentrated and then cooled. The suspension was then filtered at 10°C. The isolated product (6.46 kg, 52.2%) was dried under vacuum. The purity of the isolated product was of the order of 78% for (Z) and 22% for (E).

Step (ii):

At 50°C, water (80ml) was flowed into a medium comprising methanol (100ml), (Z)- and (E)-nitro compounds to be reduced (20g, 0.058mol) and sodium dithionite (36.8g , 0.179mol, 3.1 equivalents). Once the reaction was complete (1 h time at 50 °C), hydrochloric acid (36.3 ml, 0.406 mol) was added. Workup was carried out by adding water (70ml) and DCM (80ml) followed by sodium hydroxide (lye 30.5%, 10N) to pH=7. After re-extraction with DCM (20ml) the aqueous phase was removed, then the DCM phase was concentrated in vacuo (about 200mbar, 35°C) and replaced with acetonitrile (160ml); a solvent switch from DCM to acetonitrile was performed under reduced pressure to maintain the reaction The volume is about 200ml. A solution of hydrogen chloride in methanol (27 ml, 0,081 mol) was flowed in, then the solvent was evaporated under reduced pressure (90 mbar), and a solvent switch from methanol-acetonitrile to acetonitrile was performed with a constant volume of about 233 ml. At the end of the solvent switch, the total volume (solvent+organic compound) was adjusted to 280ml.

The suspension is then obtained in the form of white broth. Benzyl alcohol (46 ml) was then added to the suspension at 45±3°C. After cooling to 25° C., the medium was then filtered, washed with acetonitrile (30 ml) and benzyl alcohol (3.3 ml). The isolated product (11.7 g, 74.4%) was then dried under vacuum. The product was 99.93% pure for (Z) and 0.07% for (E) as determined by HPLC. At the end of step (ii), the salt of the (Z)-amino compound is thus simply and directly obtained in good purity.

Step (iii):

At 20°C, TEA (53.4ml, 0.383mol) and then a solution of T3P in DCM (154g, 0.242mol) were flowed into a medium consisting of DCM (500ml), (Z)-amino compound (50g, 0.142 mol) and PG=BOC of double-protected L-serine of formula (II) (L-serine-N-BOC-acetonide, 41.8 g, 0.170 mol). The medium was brought to reflux and water (500ml) was added. After separation by settling and concentration, methanolic hydrogen chloride (189.5 ml, 1.136 mol) and methanol (189.5 ml) were added. Water (300ml) was added to the medium and the phases were separated by settling. Isopropyl acetate (650ml) was added to the aqueous phase, followed by sodium hydroxide (115ml, 1.150mol) at 20°C. The organic phase separated and washed by settling was concentrated in vacuo and then heated to 65°C. Methanol (35ml) and methanolic hydrogen chloride (47.4ml, 0.142mol) were added at this temperature. After cooling and filtration, the product was isolated (49.6 g, 79.5%). The purity of the final product was 99.2%.

Embodiment 2 (according to the present invention)

In a jacketed 1.6-liter reactor, (Z)-amino compound-Z-aminostilbene HCl (Z-aminostil, HCl, 50.0 g), N-BOC-acetonate (41.8 g) and 500ml of DCM. Then 53.4 ml of triethylamine (2.7 equiv) was flowed in at 22±3°C, followed by a 50% solution of T3P in DCM (1.7 equiv). The mixture was stirred under reflux of DCM for 1 hour. The mixture was then cooled to 22±3°C and 500 ml of demineralized water was added. The mixture was separated by settling and the phases were separated. The DCM phase was washed with 500 ml of a 6 wt % (30 g) aqueous solution of sodium hydrogen phosphate and then with 500 ml of demineralized water. The DCM phase was concentrated at about 40-50° C. under reduced pressure of 360 to 150 mbar. A 3 mol/l solution of HCl in methanol (379 ml, 8 equivalents) was then flowed in, followed by 300 ml of demineralized water. The mixture was separated by settling and the phases were separated. The DCM/methanol phase was extracted by rinsing with demineralized water (200ml) and the phases were separated. 650 ml of isopropyl acetate were added, followed by 115 ml of 30% sodium hydroxide solution (8.1 equivalents). The mixture was separated by settling, and the organic phase was washed with 400 ml of demineralized water. The mixture was separated by settling and the phases were separated. The organic phase was then concentrated under reduced pressure from 160 to 60 mbar until 300-350 ml was obtained, and a solvent switch from DCM to isopropyl acetate was performed. Then the mixture was heated at 62° C., 35 ml of methanol was added, and 3 mol/l of hydrogen chloride in methanol (47.4 ml, 1 eq.) was flowed in. The resulting product was then allowed to cool to ambient temperature and the white broth was filtered. The final solid was washed.

In Examples 3-6, step (ii) was repeated initially with different amounts of (Z)- and (E)-nitro compounds. The ratio of acetonitrile/salts of (Z)- and (E)-amino compounds was fixed at 10.8, and the ratio of benzyl alcohol/salts of (Z)- and (E)-amino compounds was varied for its part.

Embodiment 3 (according to the present invention)

At 50° C., water (60 ml) was flowed into a medium containing methanol (50 ml), (Z)- and (E)-nitro compounds to be reduced (15 g, 0.043 mol) and sodium dithionite (27.2 g, 0.133mol). Once the reaction was complete, hydrochloric acid (26.2ml, 0.314mol) was added. Work up by adding water and DCM followed by sodium hydroxide to pH=7. Hydrogen chloride in methanol (18.9 ml, 0.0586 mol) was added to the DCM phase, and the solvent was then replaced with acetonitrile. Then get the broth. Benzyl alcohol (31 ml) was then added to the suspension at 50°C and kept at 65°C for 2 hours. After cooling, the medium is then filtered and washed. The isolated product was then dried under vacuum.

Embodiment 4-6: the same as embodiment 3, except that the amount of benzyl alcohol is different.

Table I

The ratio of acetonitrile/Z+E salt of amino compound=10.8

In Examples 5 and 7-9, the ratio of benzyl alcohol/(Z)- and (E)-amino compound salts was fixed at 2.25, and the ratio of acetonitrile/(Z)- and (E)-amino compound salts was change.

Table II

The ratio of benzyl alcohol/salt of Z+E amino compound=2.25

Examples 10-14 describe the results of coupling (step (iii)) using coupling reagents other than T3P.

Embodiment 10 (comparative example): use TOTU

The conditions of step (iii) were repeated, but in the presence of TOTU as acid activator (1 equivalent of TOTU + 5 equivalents of TEA). Then, the final yield was only 71%.

Embodiment 11 (comparative example): use TOTU

TEA (0.71 g, 7.0 mmol) and then TOTU (0.46 g, 1.4 mmol) were flowed at 5° C. into a medium containing DCM (10 ml), (Z)-amino compound (0.50 g , 1.4 mmol) and PG=BOC of double-protected L-serine of formula (II) (L-serine-N-BOC-acetonide; 0.35 g, 1.4 mmol). The medium was kept at 5° C. for 24 hours, then water (5 ml) was added. After separation by settling, the organic phase was analyzed by HPLC. The quantitatively determined yield of the coupled product was 50.1%, and its purity was 69.3%.

Embodiment 12 (comparative example): use BOP-Cl (two (2-oxo-3-oxazolidinyl) phosphonic chloride (bis(2-oxo-3-oxazolidinyl)phosphinic chloride))

NMM (0.42 g, 4.2 mmol) and then BOP-Cl (0.72 g, 2.8 mmol) were flowed into a medium containing DCM (5 ml), (Z)-amino compound (0.50 g, 1.4 mmol) at 5°C ) and PG=BOC of double protected L-serine of formula (II) (L-serine-N-BOC-acetonide; 0.35 g, 1.4 mmol). The medium was kept at 5° C. for 24 hours, then water (5 ml) was added. After separation by settling, the organic phase was analyzed by HPLC. The quantitatively determined yield of the coupled product was 29.1%, and its purity was 91.6%.

Embodiment 13 (comparative example): use PyClOP (chlorotripyrrolidino phosphonium hexafluorophosphate (chlorotripyrrolidinophosphonium hexafluorophosphate))

NMM (0.42 g, 4.2 mmol) and then PyClOP (1.2 g, 2.8 mmol) were flowed at 5°C into a medium containing ethyl acetate (10 ml), (Z)-amino compound (0.50 g, 1.4 mmol) ) and PG=BOC of double protected L-serine of formula (II) (L-serine-N-BOC-acetonide; 0.70 g, 2.8 mmol). The medium was kept at 5° C. for 24 hours, then water (5 ml) was added. After separation by settling, the organic phase was analyzed by HPLC. The quantitatively determined yield of the coupled product was 53.3%, and its purity was 83.9%.

Example 14 (comparative example): using PyBROP (bromotripyrrolidinophosphonium hexafluorophosphate)

NMM (0.42 g, 4.2 mmol) and then PyBROP (0.65 g, 1.4 mmol) were flowed into a medium containing Me-CN (5 ml), (Z)-amino compound (0.50 g, 1.4 mmol) at 25°C ) and PG=BOC of double protected L-serine of formula (II) (L-serine-N-BOC-acetonide; 0.35 g, 1.4 mmol). The medium was kept at 25° C. for 24 hours, then water (5 ml) was added. After separation by settling, the organic phase was analyzed by HPLC. The quantitatively determined yield of the coupled product was 24.9%, and its purity was 75.4%.

Table III

Note that T3P can achieve better yields than TOTU, BOP-Cl, PyClOP or PyBROP in terms of coupling products.

Claims (17)

1. the method for preparing the combretastatin (A) of alkali form or acid salt form:

Described method comprises:

At alkali and having in the presence of the T3P of formula (III),

Make (Z)-aminocompound

Or (Z)-salt of aminocompound

And have formula

The L-serine derivative couplings of two protections, thereby obtain the having formula compound of (Z)-(Ib):

B wherein ^-The expression counter anion, PG represents to protect the group of amido functional group;

In the presence of acid, carry out deprotection and open the ring of (Z)-(Ib), thereby obtain the combretastatin with formula (A) of salt form then;

And randomly, add alkali, thus the combretastatin with formula (A) of alkali form obtained,

The salt of described (Z)-aminocompound obtains by the salt of the aminocompound with following formula of enrichment (Z) isomeric forms:

B wherein ^-The expression counter anion, described enrichment comprises:

In the suspension of mixture in acetonitrile of the salt of the salt of (Z)-aminocompound and (E)-aminocompound, add phenylcarbinol, then

Mechanical separation is with the salt of the described aminocompound of (Z) isomeric forms enrichment.

2. the method for the salt of the aminocompound with following formula of enrichment (Z) isomeric forms

B wherein ^-The expression counter anion, described method comprises:

In the suspension of mixture in acetonitrile of the salt of the salt of (Z)-aminocompound and (E)-aminocompound, add phenylcarbinol and

Mechanical separation is with the salt of the described aminocompound of (Z) isomeric forms enrichment.

3. according to the method for claim 1 or 2, wherein, described mechanical separation is to filter.

4. the method for preparing the combretastatin (A) of alkali form or acid salt form:

Described method comprises:

In the presence of alkali and T3P, make (Z)-aminocompound

Or (Z)-salt of aminocompound And have formula

The L-serine derivative couplings of two protections, thereby obtain the having formula compound of (Z)-(Ib):

B wherein ^-The expression counter anion, PG represents to protect the group of amido functional group;

Then in the presence of acid, carry out deprotection and open the ring of (Z)-(Ib), thereby obtain the combretastatin (A) of salt form;

Randomly, add alkali, thereby obtain the Bu Tating (A) of alkali form.

5. according to each method in the claim 1 to 4, wherein PG represents BOC, CBZ or FMOC.

6. according to each method in the claim 1 to 5, wherein B ^-Expression Cl ^-Or SO ₄ ^2-

7. according to each method in the claim 1 to 6, wherein PG represents BOC, B ^-Expression Cl ^-

8. according to each method in the claim 1 to 7, wherein said alkali is tertiary amine.

9. method according to Claim 8, wherein said alkali is triethylamine (TEA), diisopropylethylamine (DIEA), N-methylmorpholine (NMM) or methyl piperidine.

10. according to each method in the claim 1 to 9, the salt of wherein said (Z)-aminocompound or (Z)-aminocompound and formula (II) compound one are reacting in same container in the presence of T3P and the alkali.

11. according to each method in the claim 1 to 10, wherein acetonitrile with the salt of (Z)-aminocompound and (E)-salt of aminocompound be 5 to 17 than by weight, be preferably 10 to 12.

12. according to each method in the claim 1 to 11, the temperature that wherein said enrichment is carried out is 20 to 70 ℃.

13. according to each method in the claim 1 to 12, wherein phenylcarbinol with the salt of (Z)-aminocompound and (E)-salt of aminocompound be 1 to 4 than by weight, preferred 2 to 3.

14. have the purposes of the T3P of formula (III),

Described T3P with formula (III) is used to make and has formula

(Z)-aminocompound or have formula

(Z)-aminocompound salt with have a formula

The L-serine derivative couplings of two protections, B wherein ^-The expression counter anion, PG represents to protect the group of amido functional group.

15. according to the purposes of claim 14, wherein PG represents BOC, CBZ or FMOC, and/or B ^-Expression Cl ^-Or SO ₄ ^2-

16. according to the purposes of claim 14 or 15, wherein said alkali is tertiary amine.

17. according to each purposes in the claim 14 to 16, the salt of wherein said (Z)-aminocompound or (Z)-aminocompound and formula (II) compound one are reacting in same container in the presence of T3P and the alkali.